261656511 has 8 divisors (see below), whose sum is σ = 354594864. Its totient is φ = 171577920.

The previous prime is 261656501. The next prime is 261656557. The reversal of 261656511 is 115656162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261656511 - 2¹³ = 261648319 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261656501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 714726 + ... + 715091.

It is an arithmetic number, because the mean of its divisors is an integer number (44324358).

Almost surely, 2^261656511 is an apocalyptic number.

261656511 is a deficient number, since it is larger than the sum of its proper divisors (92938353).

261656511 is a wasteful number, since it uses less digits than its factorization.

261656511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1429881.

The product of its digits is 10800, while the sum is 33.

The square root of 261656511 is about 16175.8001656796. The cubic root of 261656511 is about 639.6030342656.

The spelling of 261656511 in words is "two hundred sixty-one million, six hundred fifty-six thousand, five hundred eleven".